Document as thoroughly as possible the operations and results of the DuPont Bladder Cancer Screening Program so as to aid in the evaluation of such screening at the present time. Such documentation of a screening program involves a description of the population which is screened, a description of the screening test and its application to the population, and a description of the results of the interaction between the test and the population in terms of incidence and mortality outcome measures. The product of this investigation will be in two parts. The first is a detailed study of exposure-natural history relationships and estimation of latent period. The second is a characterization of the potential for urinary cytology to detect early bladder cancer and a qualification of the survival experience of cases detected both within and outside the screening program.